Lighting instruments are used to illuminate performers of live theater, dance, musicals, and in the production of television and movie programs. In addition, colored lighting is employed in various locations for calling attention to a certain area for the creation of mood or style. To produce colored lighting, a colored transparent lens is positioned in a so-called "color frame", and the color frame then juxtaposed with the light.
Historically, colored transparent material was supplied in sheets, referred to as gel, that were sliced from blocks of colored gelatin, and the sheets were then cut as appropriate to shape the material for the desired lens size and shape. Colored synthetic polymer composition material has replaced sheets of gel and is often referred to as "color." In this disclosure, that kind of material will be referred to as "colored transparent material".
The colored transparent material, once cut to size to establish a lens, is placed in a color frame for use in a lighting instrument. The type of lighting instrument in which the colored transparent material is used usually consists of a light bulb or other light source, a reflector, means for focusing the light output, and a slot to hold the color frame.
Unfortunately, existing methods for cutting the sheets to size are both inaccurate and inefficient, particularly when undertaken by unskilled cutting people who consequently require supervision to ensure that the correct size pieces are accurately cut with a minimum of material wastage. As examples of existing methods of cutting the sheets to size and shape, specific color frame (i.e., lens) dimensions are first obtained to determine the desired size. The colored transparent material can be put on a paper cutter, but such are heavy, expensive, and awkward to use, especially in the sizes required to handle larger sheets of colored transparent material. In addition, paper cutters provide no more information than a ruler at one edge and a cutting blade at a right angle with respect thereto. Consequently, when using a paper cutter, over-cutting is common, and material is wasted as a result. Moreover, with a paper cutter, the blades can become dull, causing the colored transparent material to be dragged off the cutting surface without being cut. If two cuts are to be made, the sheet of colored transparent material must be turned over and rotated to be lined up with the correct measurement in order to make the second cut.
Another method is to use the lens color frame (or one of the same size and shape) as a cutting guide, but when the color frame itself is used as a cutting guide, the result is an over-sized piece of colored transparent material. Furthermore, the upper corners of the color frames are normally cut off at an angle so that a rectangular piece of colored transparent material will extend upward as a portion to grasp to remove the colored transparent material. When the color frame is used as a guide, the user tends to cut along those angled corners to thereby defeat the purpose of the cut angle corners on the frame. The alternative is to cut the corners by free-hand. When using the color frame as a guide for cutting the colored transparent material, all sizes of color frames must be available to result in the need for extra frames.
Yet another way to cut the colored transparent material to fit the color frame is to place the colored transparent material on a smooth cutting surface. A straight edge is used in conjunction with a measuring scale. This is a time-consuming procedure and results in cutting or scratching the smooth cutting surface. Furthermore, the smooth cutting surface gives no cutting information to the user, thus requiring a skilled or supervised worker.
In any case, it is to be appreciated that all of the above-mentioned methods for cutting plastic sheets for various types of lights tend to be time-consuming and tend to produce inaccurately sized light covers, particularly when undertaken by unskilled people. As recognized by the present invention, it is desirable to enable an unskilled person to cut the material while avoiding the need for close supervision, which is otherwise time consuming and inefficient.